1. Field of the Invention
The present invention relates to a device for supporting and turning over board-like objects, covered on at least one side with a substance, to be dried in a continuous-circulation oven. The invention relates in particular to a device which allows the efficient drying of support boards for printed circuits.
2. Description of Related Art
It is known from the prior art that the support boards which must receive printed electronic circuits are provided with the design of the future printed circuit (layout), for example by means of photographic processes or with the aid of printing processes mainly silk-screen printing processes.
After applying onto the support board the corresponding design of the electronic circuit, the layer of ink of the design or layout must be subjected to a delicate drying procedure, enabling the board to be subjected subsequently to further operating stages, known from the art.
The time required to dry the layer of ink applied by means of the silk-screen process lasts several minutes and, obviously, during this period, the silk-screen printed boards must be treated with maximum care, precisely to prevent the fresh layer of ink, which requires the time mentioned in order to dry completely, from being irreparably damaged.
Therefore, subsequent to the silk-screen printing machine used to make printed circuits, hitherto it was usual to remove manually the silk-screen printed support boards, arranging them delicately and individually on trolleys having various surfaces located one above the other for receiving the boards. Then, these trolleys were introduced into a drying chamber, in which they remained for a certain period of time, so as to allow drying of the ink applied previously by means of the silk-screen process on at least one side of the support board.
It can be easily understood that this procedure interrupted in a completely undesirable manner the automated process for production of the support boards for electronic circuits Furthermore, this procedure required considerable manpower and rejects could not be avoided.
It would, of course, be conceivable to construct a drying oven through which the support boards to be dried would pass in the longitudinal direction but, since the drying stage requires a considerable amount of time, it is obvious that this oven would have to have dimensions which would no longer be acceptable from a technical and economic point of view.